Selective metal removal with flowable polymer

ABSTRACT

Embodiments of the disclosure relate to methods for selectively removing metal material from the top surface and sidewalls of a feature. The metal material which is covered by a flowable polymer material remains unaffected. In some embodiments, the metal material is formed by physical vapor deposition resulting in a relatively thin sidewall thickness. Any metal material remaining on the sidewall after removal of the metal material from the top surface may be etched by an additional etch process. The resulting metal layer at the bottom of the feature facilitates selective metal gapfill of the feature.

TECHNICAL FIELD

Embodiments of the present disclosure pertain to methods of metalremoval facilitated by a flowable polymer. More particularly,embodiments of the disclosure are directed to methods of selectivelyremoving tungsten relative to a flowable polymer within a substratefeature.

BACKGROUND

Gapfill process are integral to several semiconductor manufacturingprocesses. A gapfill process can be used to fill a gap (or feature) withan insulating or conducting material. For example, shallow trenchisolation, inter-metal dielectric layers, passivation layers, dummygate, are all typically implemented by gapfill processes.

As device geometries continue to shrink (e.g., critical dimensions <20nm, <10 nm, and beyond) and thermal budgets are reduced, defect-freefilling of spaces becomes increasingly difficult due to the limitationsof conventional deposition processes.

Processes for selective tungsten fill have been implemented whereintungsten can be selectively deposited on a tungsten seed layer.Unfortunately, these processes both require a minimum seed layerthickness. Known PVD processes can provide the necessary seed layerthickness, but the selective tungsten fill process will deposit tungstenmaterial on any exposed seed layer.

Accordingly, there is a need for methods to remove unwanted tungstendeposition from field and sidewall surfaces in order to enable bottom upfill by selective deposition processes.

SUMMARY

One or more embodiments of the disclosure are directed to a method ofselective metal removal. The method comprises forming a flowable polymerfilm on a substrate surface with at least one feature formed therein.The at least one feature has an opening at a top surface with an openingwidth, at least one sidewall and a bottom. The at least one featureextends a feature depth from the top surface to the bottom. The flowablepolymer film is formed within the at least one feature and has a polymerdepth less than or equal to the feature depth. At least a portion of ametal material is selectively removed from the top surface withoutsubstantially affecting any material beneath the polymer film.

Additional embodiments of the disclosure are directed to a method ofselective tungsten removal. The method comprises depositing a tungstenmaterial on a substrate surface with at least one feature formedtherein. The at least one feature has an opening at a top surface withan opening width, at least one sidewall and a bottom. The at least onefeature extends a feature depth from the top surface to the bottom. Aflowable polymer film is formed within the at least one feature and hasa polymer depth less than or equal to the feature depth. At least aportion of the tungsten material is selectively removed from the topsurface without substantially affecting the tungsten material beneaththe polymer film. The polymer film is removed to expose the tungstenmaterial beneath the polymer film. The tungsten material is etched fromthe at least one sidewall. A second metal material is selectivelydeposited on the tungsten material.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the above recited features of the present disclosure can beunderstood in detail, a more particular description of the disclosure,briefly summarized above, may be had by reference to embodiments, someof which are illustrated in the appended drawings. It is to be noted,however, that the appended drawings illustrate only typical embodimentsof this disclosure and are therefore not to be considered limiting ofits scope, for the disclosure may admit to other equally effectiveembodiments

The embodiments as described herein are illustrated by way of exampleand not limitation in the figures of the accompanying drawings in whichlike references indicate similar elements.

FIG. 1 illustrates a process flow diagram of a method according to oneor more embodiment;

FIG. 2 illustrates a cross-sectional view of a substrate featureaccording to one or more embodiment;

FIGS. 3-10 illustrate a cross-sectional view of a substrate duringprocessing according to one or more embodiment; and

FIG. 11 is a schematic top-view diagram of an exemplary multi-chamberprocessing system according to one or more embodiment.

DETAILED DESCRIPTION

Before describing several exemplary embodiments of the disclosure, it isto be understood that the disclosure is not limited to the details ofconstruction or process steps set forth in the following description.The disclosure is capable of other embodiments and of being practiced orbeing carried out in various ways.

The term “about” as used herein means approximately or nearly and in thecontext of a numerical value or range set forth means a variation of±15% or less, of the numerical value. For example, a value differing by±14%, ±10%, ±5%, ±2%, ±1%, ±0.5%, or ±0.1% would satisfy the definitionof about.

As used in this specification and the appended claims, the term“substrate” or “wafer” refers to a surface, or portion of a surface,upon which a process acts. It will also be understood by those skilledin the art that reference to a substrate can refer to only a portion ofthe substrate, unless the context clearly indicates otherwise.Additionally, reference to depositing on a substrate can mean both abare substrate and a substrate with one or more films or featuresdeposited or formed thereon.

A “substrate” as used herein, refers to any substrate or materialsurface formed on a substrate upon which film processing is performedduring a fabrication process. For example, a substrate surface on whichprocessing can be performed include materials such as silicon, siliconoxide, strained silicon, silicon on insulator (SOI), carbon dopedsilicon oxides, amorphous silicon, doped silicon, germanium, galliumarsenide, and any other materials such as metals, metal nitrides, metalalloys, and other conductive materials, depending on the application.Substrates include, without limitation, semiconductor wafers. Substratesmay be exposed to a pretreatment process to polish, etch, reduce,oxidize, hydroxylate, anneal and/or bake the substrate surface. Inaddition to film processing directly on the surface of the substrateitself, in the present disclosure, any of the film processing stepsdisclosed may also be performed on an under-layer formed on thesubstrate as disclosed in more detail below, and the term “substratesurface” is intended to include such under-layer as the contextindicates. Thus, for example, where a film/layer or partial film/layerhas been deposited onto a substrate surface, the exposed surface of thenewly deposited film/layer becomes the substrate surface.

As used herein, the term “substrate surface” refers to any substratesurface upon which a layer may be formed. The substrate surface may haveone or more features formed therein, one or more layers formed thereon,and combinations thereof. The shape of the feature can be any suitableshape including, but not limited to, peaks, trenches, holes and vias(circular or polygonal). As used in this regard, the term “feature”refers to any intentional surface irregularity. Suitable examples offeatures include but are not limited to trenches, which have a top, twosidewalls and a bottom extending into the substrate, vias which have oneor more sidewall extending into the substrate to a bottom and slot vias.

As used in this specification and the appended claims, the term“selectively” refers to process which acts on a first surface with agreater effect than another second surface. Such a process would bedescribed as acting “selectively” on the first surface over the secondsurface. The term “over” used in this regard does not imply a physicalorientation of one surface on top of another surface, rather arelationship of the thermodynamic or kinetic properties of the chemicalreaction with one surface relative to the other surface.

The term “on” indicates that there is direct contact between elements.The term “directly on” indicates that there is direct contact betweenelements with no intervening elements.

As used in this specification and the appended claims, the terms“precursor”, “reactant”, “reactive gas” and the like are usedinterchangeably to refer to any gaseous species that can react with thesubstrate surface.

Embodiments of the disclosure advantageously provide methods forselectively removing a metallic material from a substrate surface. Someembodiments advantageously provide for the removal of a metallicmaterial from the field and sidewalls of a feature without removal fromthe bottom surface of the substrate. Further embodiments advantageouslyprovide methods of depositing an etch stop layer comprising a flowableorganic polymer. Additional embodiments advantageously provide methodsfor forming metallic gapfill in a bottom-up fashion.

The embodiments of the disclosure are described by way of the Figures,which illustrate processes and substrates in accordance with one or moreembodiments of the disclosure. The processes, schema and resultingsubstrates shown are merely illustrative of the disclosed processes, andthe skilled artisan will recognize that the disclosed processes are notlimited to the illustrated applications.

Referring to the Figures, the disclosure relates to a method 100 ofselective metal removal. FIG. 1 depicts a process flow diagram of aselective metal removal method 100 in accordance with one or moreembodiment of the present disclosure. FIG. 2 depicts a substrate 200having a substrate surface with at least one feature formed therein.FIGS. 3-10 depict a substrate during processing according to one or moreembodiment of the present disclosure.

FIG. 2 illustrates a substrate 200 with a substrate surface 205. Asidentified above, the substrate surface refers to the exposed surface ofthe substrate upon which a process may be performed. The substratesurface 205 has at least one feature 210 formed therein. While only asingle feature is shown in the Figures, one skilled in the art willrecognize that a plurality of features will each be affected by thedisclosed methods in a similar manner.

The at least one feature 210 has an opening 212 with an opening width W.The opening 212 is formed in a top surface 215 of the substrate 200. Thefeature 210 also has one or more sidewall 214 and extends a featuredepth D from the top surface 215 to a bottom 216. While straight,vertical sidewalls are shown in the Figures, the disclosed methods mayalso be performed on slanted, irregular or reentrant sidewalls.

While the substrate 200 illustrated in FIG. 2 is comprised of a singlematerial 220, those skilled in the art will recognize that the topsurface 215, sidewall 214 and bottom 216 may each be comprised of one ormore similar or different materials. For example, the lower portion ofsidewall 214 may be formed from a first material while the upper portionof the same sidewall 214 may be comprised of a second material.Similarly, a thin layer may be deposited on the top surface 215 withoutforming an appreciable portion of the sidewall 214. Further, the bottom216 may be comprised of a different material than the sidewall 214.

In some embodiments, the opening width W of the opening 212 is less thanor equal to about 50 nm, less than or equal to about 30 nm, less than orequal to about 20 nm, less than or equal to about 10 nm, or less than orequal to about 7 nm. In some embodiments, the opening width W is in arange of about 8 nm to about 20 nm.

In some embodiments, the feature depth D of the feature 210 is greaterthan or equal to about 20 nm, greater than or equal to about 50 nm,greater than or equal to about 60 nm, greater than or equal to about 75nm, or greater than or equal to about 90 nm. In some embodiments, theopening width W is in a range of about 60 nm to about 100 nm.

In some embodiments, the at least one feature 210 has an aspect ratio(D/W) in a range of about 1 to about 20 or in a range of about 2 toabout 15.

For simplicity, reference will be made to parts of the feature 210illustrated in FIG. 2 while referring to FIGS. 3-10 . For example, thesubstrate 300 shown in FIG. 3 will be referred to as having a bottom216. For clarity of the illustrations provided, the reference numeralsof the parts of feature 210 are not shown in FIGS. 3-10 .

Referring to FIGS. 1 and 3-10 , in some embodiments, the method 100begins with optional operation 105 to pre-treat the substrate. Thepre-treatment at operation 105 can be any suitable pre-treatment knownto the skilled artisan. Suitable pre-treatments include, but are notlimited to, pre-heating, cleaning, soaking, native oxide removal, ordeposition of an contact layers (e.g. titanium silicide (TiSi)), orcapping layers (e.g., TiSiN). In some embodiments, a layer such astitanium silicide or TiSiN is deposited at operation 105.

An exemplary substrate 300 is shown in FIG. 3 after optional operation105. The substrate 300 comprises a bottom formed from layer 310 andsidewalls and a top surface formed from layer 320. In some embodiments,layer 310 comprises a conductive material and layer 320 comprises adielectric. Those skilled in the art will recognize that the disclosedprocesses may be performed on different materials and/or that theillustrated layers may be arranged in different ways.

The method 100 continues with cycle 110. Cycle 110 forms a layer ofmetal material 410 at the bottom 216 of at least one feature 210 of thesubstrate 300. Cycle 110 includes a series of operations which are eachperformed in sequence and may be repeated. Some of the operations areoptional within each cycle. A given optional operation may be performedduring each cycle, periodically (every other, every fifth or everyhundredth cycle), as needed based on predetermined parameters, or evennot at all.

As shown in FIG. 4 , the cycle 110 begins with optional operation 112.At 112, a metal material 410 is deposited on the substrate surface 205of the substrate 300. The metal material 410 has a bottom thickness onthe bottom 216 and a top thickness on the top surface 215 and/or asidewall thickness on the sidewall 214.

The metal material may be deposited by any suitable method. In someembodiments, the metal material 410 may be deposited by physical vapordeposition (PVD). In these embodiments, as shown in FIG. 4 , thesidewall thickness is less than the top thickness and the bottomthickness. In some embodiments, the top thickness is greater than thebottom thickness.

Those skilled in the art will recognize that the disclosed methods maybegin with a metal material 410 formed on the substrate surface 205 ofthe substrate 300. Accordingly, operation 112 is disclosed as optional.

The cycle 110 continues with operation 114. As shown in FIG. 5 , at 114,a flowable polymer film 510 is formed within the feature 210 of thesubstrate 300. The polymer film 510 has a polymer depth less than orequal to the feature depth D. Stated differently, as a flowable film(described below), the polymer film is contained entirely with thefeature 210 and is not present on the top surface 215 of the substrate300. In some embodiments, the polymer film has a depth in a range ofabout 1 nm to about 10 nm, or in a range of about 2 nm to about 5 nm.

In the disclosed methods, processing parameters and reactants may beselected to limit conformality of deposited materials, which may allowthe deposited material to better fill features on the substrate. Aflowable material is one which, under the proper conditions will flow bygravity to the low point of a substrate surface and/or by capillaryaction to narrow CD spaces of trenches or other features.

In some embodiments, forming the polymer film comprises exposing thesurface to one or more monomers. In some embodiments, the monomersconsist essentially of a single, bi-functional monomer, each functionalgroup being different. In this way, one functional group of a monomermolecule will react with the other functional group of a differentmonomer molecule. Those skilled in the art may recognize this as an “A”polymer.

In some embodiments, the one or more monomers comprise or consistessentially of methacrylate, styrene, benzyl alcohol, benzyl chloride orderivatives thereof. As used in this regard, a derivative of a basemolecule may contain one or more group comprising 1-10 carbon atoms. Forexample, in some embodiments, the methacrylate compound has a generalformula of:

where R is a group comprising 1-10 carbon atoms and R′ is a groupcomprising 1-6 carbon atoms. As used in this regard, a group comprisingcarbon atoms may be linear, branched, cyclic, saturated or unsaturated.The groups comprising carbon atoms disclosed herein do not containgroups which are reactive in the chemical polymerization processdescribed herein.

Additionally, a styrene derivative monomer may include a group on thebenzene ring with 0-10 carbon atoms and an R′ group on the vinylcomprising 1-6 carbon atoms. A benzyl alcohol derivative monomer or abenzyl chloride derivative monomer may include a group on the benzenering comprising 0-10 carbon atoms and a R′ group on the benzyl carboncomprising 1-6 carbon atoms.

In some embodiments, the monomers consist essentially of twobifunctional monomers, each functional group being the same. In this waythe functional groups of one monomer react with the functional groups ofa second monomer. Those skilled in the art may recognize this as an “AB”polymer.

In some embodiments, the monomers comprise at least two amine, aldehyde,ketone, or alcohol groups. In some embodiments, the monomers have ageneral formula of X—R″—X, where X is a functional group selected fromNH₂, NHR′, O, OH, CHO, CR′O, COOH, or COOR′, R′ is a group comprising1-6 carbon atoms, and R″ is a group comprising 1-15 carbon atoms. Insome embodiments, R′ comprises 1-4 carbon atoms. In some embodiments, R″is an ethylene or propylene group. In specific embodiments, the monomerscomprise terephthalic acid (TPA, C₆H₄(COOH)₂) and ethylene diamine(C₂H₄(NH₂)₂).

In some embodiments, the monomers include a monofunctional monomer. Whencombined with the above embodiments, those skilled in the art mayrecognize this as an “AC” or “ABC” polymer. Without being bound bytheory, in these embodiments, it is believed that the monofunctionalmonomer acts as a terminal group and limits any further chain reactions.

In some embodiments, the monofunctional monomer comprises an amine,aldehyde, ketone, or alcohol group. In some embodiments, themonofunctional monomer has a general formula of RX, where R is a groupcomprising 1-10 carbon atoms, X is a functional group selected from NH₂,NHR′, O, OH, or COOH, and R′ is a group comprising 1-6 carbon atoms.

As stated previously, the polymer film 510 is flowable. In order tocontrol the “flowability” of the resulting film, it has been found thatit is necessary to control the size of the resulting oligomers.

Accordingly, in some embodiments, the formation of the polymer film 510is performed on a substrate maintained at a temperature in a range of 0°C. to 400° C. In some embodiments, the substrate is maintained at atemperature greater than or equal to about 0° C., greater than or equalto about 30° C., greater than or equal to about 50° C., greater than orequal to about 100° C., greater than or equal to about 200° C., orgreater than or equal to about 300° C. In some embodiments, thesubstrate is maintained at a temperature less than or equal to about400° C., less than or equal to about 300° C., less than or equal toabout 200° C., less than or equal to about 100° C., less than or equalto about 50° C., or less than or equal to about 30° C.

Further, other process parameters may be controlled during the formationof the polymer film 510. Examples of parameters which may be controlledinclude, but are not limited to: processing chamber pressure, monomerselections, the use of an inert diluent or carrier gas, partialpressures of monomers, pulse sequence of monomers, and pause periods topermit flow of the polymer material.

The cycle 110 continues with operation 116. As shown in FIG. 6 , at 116,at least a portion of the metal material 410 is selectively removed. Themetal material 410 is removed from the top surface 215 withoutsubstantially affecting any material beneath the polymer film. As usedin this regard, a process which does not “substantially affect” materiallayers does not cause any decrease in volume, thickness or composition.One skilled in the art will recognize that the polymer film 510 isacting as an etch stop layer during the removal of a portion of themetal material 410.

In some embodiments, operation 116 also removes a portion of the metalmaterial 410 from the sidewall 214. In some embodiments, any metalmaterial 410 which is present on sidewall 214 below the upper surface ofthe polymer film 510 may remain intact without being removed.

In some embodiments, the selective removal of the metal material 410 isperformed by exposing the substrate surface 205 of substrate 300 to NF₃radicals. In some embodiments, the substrate is maintained at atemperature in a range of 80° C. to 110° C.

In some embodiments, the selective removal of metal material 410 isperformed by a sequence of oxidizing metal material 410 and exposing theoxidized material to a metal halide to etch the oxidized material. Insome embodiments, when the metal material comprises tungsten, the metalhalide comprises WCl₅.

The cycle 110 continues with optional operation 118. As shown in FIG. 7, at 118, the polymer film 510 is removed to expose the metal material410 beneath the polymer film 510. In some embodiments, the removal ofthe polymer film 510 leaves residue of the polymer film 510, shown as Xon the surface of the metal material 410. In some embodiments, theremoval of the polymer film 510 is complete and leaves no residues.

In some embodiments, the polymer film 510 is removed by exposing thesubstrate surface 205 of the substrate 300 to a H₂ plasma treatment. Insome embodiments, the polymer film 510 is removed by exposure to an O₂plasma. In some embodiments, the polymer film 510 is removed by exposureto a thermal O₂ environment at an elevated temperature.

The cycle 110 continues with optional operation 119. As shown in FIG. 8, at 119, the residue X, if present, is cleaned from the surface of themetal material 410. The cleaning process can be any suitable processwhich cleans the surface of the metal material. In some embodiments, thecleaning process does not oxidize the metal surface.

In some embodiments, at the end of cycle 110, the surface of the metalmaterial 410 does not contain any contaminants or residues of thepolymer layer 410. Specifically, In some embodiments, there are nocarbon or oxygen residues on the surface of the metal material 410. Insome embodiments, when the method 100 includes repeated cycles 110 (seebelow), there are no contaminants or residues between amounts of themetal material 410 deposited in subsequent cycles. In some embodiments,when the method 100 includes the deposition of a second metal material1010 (see below), there are no contaminants or residues between themetal material 410 are the second metal material 1010.

In some embodiments, this is achieved by a removal process at operation118 which leaves no residues or contaminants. In some embodiments, thisis achieved by performing a clean process at operation 119. In someembodiments, the monomers are selected so as not to contain any oxygenatoms which may oxidize the surface of the metal material 410 duringremoval of the polymer layer 510.

The method 100 continues to decision point 120. At point 120, thesubstrate is evaluated to determine whether or not the metal material410 has reached a predetermined thickness or a predetermined number ofcycles 110 have been performed. If the conditions are met, the method100 continues to operation 130. If the conditions are not met, themethod 100 returns to the beginning of cycle 110 with operation 112. Inthose embodiments in which the cycle 110 is repeated to form additionalmaterial, those skilled in the art will appreciate that operation 112 isoften performed to deposit the requisite additional metal material. Insome embodiments, the predetermined thickness is in a range of about 2nm to about 10 nm.

The method 100 continues with optional operation 130. As shown in FIG. 9, at 130, the metal material 410 is etched. In some embodiments, themetal material 410 is etch to remove the portions of the metal material410 which extend up the sidewall 214. When etched, the metal material410 is also thinned on the bottom 216 of the feature 210. Accordingly,one skilled in the art will recognize that the metal material 410 may bedeposited to a greater bottom thickness than desired in a final productto provide for sacrificial material which will be removed when etchingthe metal material from the sidewall 214.

Without being bound by theory, the inventors have found that the removalof the sidewall portions of the metal material 410 simplifies thesubsequent deposition of a second metal material 1010 at operation 140.The even, flat surface provided by operation 130 allows for the secondmetal material 1010 to grow in a bottom-up fashion without lateralgrowth from the sidewall 214.

The method 100 continues at optional operation 140. As shown in FIG. 10, at 140, a second metal material 1010 is selectively deposited on themetal material 410. The deposition process is selective to the surfaceof the metal material 410 over other substrate surface materials (e.g.layer 320). The selective deposition process provides a gapfill materialcomprising the second metal material 1010 which is formed in a bottom-upfashion without lateral deposition from the sidewall 214. In someembodiments, the second metal material is deposited without forming anyvoids or seams within the second metal material 1010.

In some embodiments, the metal material 410 and the second metalmaterial 1010 comprise the same metal. In some embodiments, the metalmaterial 410 and the second metal material 1010 comprise differentmetals. In some embodiments, the first metal material comprises orconsists essentially of tungsten, molybdenum, or ruthenium.

The method may end after operation 140 or it may continue with optionalpost processing at optional operation 150. The optional post-processingoperation 150 can be, for example, a process to modify film properties(e.g., annealing or plasma treatment), a further film deposition process(e.g., additional ALD or CVD processes) to grow additional films, or afurther etch process to form a desired predetermined devicearchitecture. In some embodiments, the optional post-processingoperation 150 can be a process that modifies a property of the depositedfilm. In some embodiments, the optional post-processing operation 150comprises annealing the substrate 300. In some embodiments, annealing isperformed at a temperature greater than or equal to about 300° C.,greater than or equal to about 400° C., greater than or equal to about500° C., greater than or equal to about 600° C., greater than or equalto about 700° C., greater than or equal to about 800° C., greater thanor equal to about 900° C. or greater than or equal to about 1000° C. Theannealing environment of some embodiments comprises one or more of aninert gas (e.g., molecular nitrogen (N₂), argon (Ar)) or a reducing gas(e.g., molecular hydrogen (H₂) or ammonia (NH₃)) or an oxidant, such as,but not limited to, oxygen (O₂), ozone (O₃), or peroxides. Annealing canbe performed for any suitable length of time. In some embodiments, thesubstrate is annealed for a predetermined time in the range of about 15seconds to about 90 minutes, or in the range of about 1 minute to about60 minutes.

FIG. 11 is a schematic top-view diagram of an exemplary multi-chamberprocessing system 1100 according to embodiments of the presentdisclosure. The processing system 1100 generally includes a factoryinterface 1102, load lock chambers 1104, 1106, transfer chambers 1108,1110 with respective transfer robots 1112, 1114, holding chambers 1116,1118, and processing chambers 1120, 1122, 1124, 1126, 1128, 1130. Asdetailed herein, wafers in the processing system 1100 can be processedin and transferred between the various chambers without exposing thewafers to an ambient environment exterior to the processing system 1100(e.g., an atmospheric ambient environment such as may be present in afab). For example, the wafers can be processed in and transferredbetween the various chambers in a low pressure (e.g., less than or equalto about 300 Torr) or vacuum environment without breaking the lowpressure or vacuum environment between various processes performed onthe wafers in the processing system 1100. Accordingly, the processingsystem 1100 may provide for an integrated solution for some processingof wafers.

Without being bound by theory, this integrated environment may aid inprocessing throughput and simplification of processing schema as cappinglayers to prevent oxidation or metals would no longer be necessary. Insome embodiments, the disclosed methods are performed without breakingvacuum.

Examples of a processing system that may be suitably modified inaccordance with the teachings provided herein include the Endura®,Producer®, or Centura® integrated processing systems or other suitableprocessing systems commercially available from Applied Materials, Inc.,located in Santa Clara, California. It is contemplated that otherprocessing systems (including those from other manufacturers) may beadapted to benefit from aspects described herein.

In the illustrated example of FIG. 11 , the factory interface 1102includes a docking station 1140 and factory interface robots 1142 tofacilitate transfer of wafers. The docking station 1140 is configured toaccept one or more front opening unified pods (FOUPs) 1144. In someexamples, each factory interface robot 1142 generally comprises a blade1148 disposed on one end of the respective factory interface robot 1142configured to transfer the wafers from the factory interface 1102 to theload lock chambers 1104, 1106.

The load lock chambers 1104, 1106 have respective ports 1150, 1152coupled to the factory interface 1102 and respective ports 1154, 1156coupled to the transfer chamber 1108. The transfer chamber 1108 furtherhas respective ports 1158, 1160 coupled to the holding chambers 1116,1118 and respective ports 1162, 1164 coupled to processing chambers1120, 1122. Similarly, the transfer chamber 1110 has respective ports1166, 1168 coupled to the holding chambers 1116, 1118 and respectiveports 1170, 1172, 1174, 1176 coupled to processing chambers 1124, 1126,1128, 1130. The ports 1154, 1156, 1158, 1160, 1162, 1164, 1166, 1168,1170, 1172, 1174, 1176 can be, for example, slit valve openings withslit valves for passing wafers therethrough by the transfer robots 1112,1114 and for providing a seal between respective chambers to prevent agas from passing between the respective chambers. Generally, any port isopen for transferring a wafer therethrough. Otherwise, the port isclosed.

The load lock chambers 1104, 1106, transfer chambers 1108, 1110, holdingchambers 1116, 1118, and processing chambers 1120, 1122, 1124, 1126,1128, 1130 may be fluidly coupled to a gas and pressure control system(not specifically illustrated). The gas and pressure control system caninclude one or more gas pumps (e.g., turbo pumps, cryo-pumps, roughingpumps), gas sources, various valves, and conduits fluidly coupled to thevarious chambers. In operation, a factory interface robot 1142 transfersa wafer from a FOUP 1144 through a port 1150 or 1152 to a load lockchamber 1104 or 1106. The gas and pressure control system then pumpsdown the load lock chamber 1104 or 1106. The gas and pressure controlsystem further maintains the transfer chambers 1108, 1110 and holdingchambers 1116, 1118 with an interior low pressure or vacuum environment(which may include an inert gas). Hence, the pumping down of the loadlock chamber 1104 or 1106 facilitates passing the wafer between, forexample, the atmospheric environment of the factory interface 1102 andthe low pressure or vacuum environment of the transfer chamber 1108.

With the wafer in the load lock chamber 1104 or 1106 that has beenpumped down, the transfer robot 1112 transfers the wafer from the loadlock chamber 1104 or 1106 into the transfer chamber 1108 through theport 1154 or 1156. The transfer robot 1112 is then capable oftransferring the wafer to and/or between any of the processing chambers1120, 1122 through the respective ports 1162, 1164 for processing andthe holding chambers 1116, 1118 through the respective ports 1158, 1160for holding to await further transfer. Similarly, the transfer robot1114 is capable of accessing the wafer in the holding chamber 1116 or1118 through the port 1166 or 1168 and is capable of transferring thewafer to and/or between any of the processing chambers 1124, 1126, 1128,1130 through the respective ports 1170, 1172, 1174, 1176 for processingand the holding chambers 1116, 1118 through the respective ports 1166,1168 for holding to await further transfer. The transfer and holding ofthe wafer within and among the various chambers can be in the lowpressure or vacuum environment provided by the gas and pressure controlsystem.

The processing chambers 1120, 1122, 1124, 1126, 1128, 1130 can be anyappropriate chamber for processing a wafer according to the method 100.In some embodiments, the processing chamber 1120 can be capable ofperforming a pre-treatment process, the processing chambers 1122, 1124can be capable of performing a deposition process, the processingchambers 1126, 1128 can be capable of performing etch processes, andprocessing chamber 1130 can be capable of performing a clean process.The processing chamber 1120 may be a SiCoNi™ Preclean chamber availablefrom Applied Materials of Santa Clara, Calif. The processing chambers1126, 1128 may be Selectra™ Etch chambers, MCxT chambers or Voltachambers, each available from Applied Materials of Santa Clara, Calif.

A system controller 1190 is coupled to the processing system 1100 forcontrolling the processing system 1100 or components thereof. Forexample, the system controller 1190 may control the operation of theprocessing system 1100 using a direct control of the chambers 1104,1106, 1108, 1116, 1118, 1110, 1120, 1122, 1124, 1126, 1128, 1130 of theprocessing system 1100 or by controlling controllers associated with thechambers 1104, 1106, 1108, 1116, 1118, 1110, 1120, 1122, 1124, 1126,1128, 1130. In operation, the system controller 1190 enables datacollection and feedback from the respective chambers to coordinateperformance of the processing system 1100.

The system controller 1190 generally includes a central processing unit(CPU) 1192, memory 1194, and support circuits 1196. The CPU 1192 may beone of any form of a general-purpose processor that can be used in anindustrial setting. The memory 1194, or non-transitory computer-readablemedium, is accessible by the CPU 1192 and may be one or more of memorysuch as random-access memory (RAM), read only memory (ROM), floppy disk,hard disk, or any other form of digital storage, local or remote. Thesupport circuits 1196 are coupled to the CPU 1192 and may comprisecache, clock circuits, input/output subsystems, power supplies, and thelike. The various methods disclosed herein may generally be implementedunder the control of the CPU 1192 by the CPU 1192 executing computerinstruction code stored in the memory 1194 (or in memory of a particularprocess chamber) as, for example, a software routine. When the computerinstruction code is executed by the CPU 1192, the CPU 1192 controls thechambers to perform processes in accordance with the various methods.

Other processing systems can be in other configurations. For example,more or fewer processing chambers may be coupled to a transferapparatus. In the illustrated example, the transfer apparatus includesthe transfer chambers 1108, 1110 and the holding chambers 1116, 1118. Inother examples, more or fewer transfer chambers (e.g., one transferchamber) and/or more or fewer holding chambers (e.g., no holdingchambers) may be implemented as a transfer apparatus in a processingsystem.

Processes may generally be stored in the memory of the system controller1190 as a software routine that, when executed by the processor, causesthe process chamber to perform processes of the present disclosure. Thesoftware routine may also be stored and/or executed by a secondprocessor (not shown) that is remotely located from the hardware beingcontrolled by the processor. Some or all of the method of the presentdisclosure may also be performed in hardware. As such, the process maybe implemented in software and executed using a computer system, inhardware as, e.g., an application specific integrated circuit or othertype of hardware implementation, or as a combination of software andhardware. The software routine, when executed by the processor,transforms the general-purpose computer into a specific purpose computer(controller) that controls the chamber operation such that the processesare performed.

Embodiments of the disclosure are directed to a non-transitory computerreadable medium. In one or more embodiments, the non-transitory computerreadable medium includes instructions that, when executed by acontroller of a processing chamber, causes a processing chamber toperform the operations of any of the methods (e.g., method 100)described herein. In one or more embodiments, the controller causes aprocessing chamber to perform the operations of method 100. In one ormore embodiments, the controller causes the processing chamber toperform the operations of forming a polymer film on the substratesurface (operation 114). In one or more embodiments, the controllercauses the processing chamber to perform the operations of removing themetal material (operation 116).

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,”“upper” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, the exemplary term “below” may encompass both anorientation of above and below. The device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the materials and methods discussed herein(especially in the context of the following claims) are to be construedto cover both the singular and the plural, unless otherwise indicatedherein or clearly contradicted by context. Recitation of ranges ofvalues herein are merely intended to serve as a shorthand method ofreferring individually to each separate value falling within the range,unless otherwise indicated herein, and each separate value isincorporated into the specification as if it were individually recitedherein. All methods described herein can be performed in any suitableorder unless otherwise indicated herein or otherwise clearlycontradicted by context. The use of any and all examples, or exemplarylanguage (e.g., “such as”) provided herein, is intended merely to betterilluminate the materials and methods and does not pose a limitation onthe scope unless otherwise claimed. No language in the specificationshould be construed as indicating any non-claimed element as essentialto the practice of the disclosed materials and methods.

Reference throughout this specification to “one embodiment,” “certainembodiments,” “one or more embodiments” or “an embodiment” means that aparticular feature, structure, material, or characteristic described inconnection with the embodiment is included in at least one embodiment ofthe disclosure. Thus, the appearances of the phrases such as “in one ormore embodiments,” “in certain embodiments,” “in one embodiment” or “inan embodiment” in various places throughout this specification are notnecessarily referring to the same embodiment of the disclosure. In oneor more embodiments, the particular features, structures, materials, orcharacteristics are combined in any suitable manner.

Although the disclosure herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent disclosure. It will be apparent to those skilled in the art thatvarious modifications and variations can be made to the method andapparatus of the present disclosure without departing from the spiritand scope of the disclosure. Thus, it is intended that the presentdisclosure include modifications and variations that are within thescope of the appended claims and their equivalents.

What is claimed is:
 1. A method of selective metal removal, the methodcomprising: forming a flowable polymer film on a substrate surface withat least one feature formed therein, the at least one feature having anopening at a top surface with an opening width, at least one sidewalland a bottom, the at least one feature extending a feature depth fromthe top surface to the bottom, the flowable polymer film formed withinthe at least one feature and having a polymer depth less than or equalto the feature depth; and selectively removing at least a portion of ametal material from the top surface without substantially affecting anymaterial beneath the polymer film.
 2. The method of claim 1, whereinforming a polymer film comprises exposing the substrate surface to oneor more monomers.
 3. The method of claim 2, wherein the monomers consistessentially of a single, bi-functional monomer.
 4. The method of claim2, wherein the monomers consist essentially of two bi-functionalmonomers.
 5. The method of claim 2, wherein the monomers comprise amono-functional terminal monomer.
 6. The method of claim 1, whereinselectively removing the metal material is performed by exposing thesubstrate surface to NF₃ radicals.
 7. The method of claim 1, furthercomprising: depositing the metal material on the substrate surfacebefore forming the polymer film, the metal material having a topthickness on the top surface and a bottom thickness on the bottom of theat least one feature.
 8. The method of claim 7, wherein the metalmaterial is deposited by physical vapor deposition (PVD) and the metalmaterial has a sidewall thickness less than the top thickness and thebottom thickness.
 9. The method of claim 1, further comprising: removingthe polymer film to expose a metal layer beneath the polymer film. 10.The method of claim 9, wherein the polymer film is removed by exposingthe substrate surface to a H₂ plasma treatment.
 11. The method of claim9, further comprising: selectively depositing a second metal material onthe metal layer.
 12. The method of claim 1, further comprising:depositing the metal material on the substrate surface before formingthe polymer film, the metal material having a top thickness on the topsurface and a bottom thickness on the bottom of the at least onefeature; removing the polymer film to expose the metal material beneaththe polymer film; and repeating a cycle of depositing the metalmaterial, forming the polymer film, selectively removing the metalmaterial, and removing the polymer film to form a predeterminedthickness of the metal material on the bottom of the at least onefeature.
 13. The method of claim 12, wherein the predetermined thicknessis in a range of about 2 nm to about 10 nm.
 14. The method of claim 12,wherein there is substantially no carbon or oxygen residue betweenlayers of the metal material at the bottom of the at least one feature.15. The method of claim 1, wherein the opening width is in a range ofabout 8 nm to about 20 nm.
 16. The method of claim 1, wherein thefeature depth is in a range of about 60 nm to about 100 nm.
 17. Themethod of claim 1, wherein a ratio of the feature depth to the openingwidth is in a range of about 2 to about
 15. 18. The method of claim 1,wherein the polymer depth is in a range of about 1 nm to about 10 nm.19. The method of claim 1, wherein the metal material comprises one ormore of tungsten, molybdenum, or ruthenium.
 20. A method of selectivetungsten removal, the method comprising: depositing a tungsten materialon a substrate surface with at least one feature formed therein, the atleast one feature having an opening at a top surface with an openingwidth, at least one sidewall and a bottom, the at least one featureextending a feature depth from the top surface to the bottom; forming aflowable polymer film within the at least one feature, the flowablepolymer film formed having a polymer depth less than or equal to thefeature depth; selectively removing at least a portion of the tungstenmaterial from the top surface without substantially affecting thetungsten material beneath the polymer film; removing the polymer film toexpose the tungsten material beneath the polymer film; etching thetungsten material from the at least one sidewall; and selectivelydepositing a second metal material on the tungsten material.